javascript 阻止事件元素默认行为和传播(冒泡)
document.getElementById('id').onclick = function(e){e = e || window.event;var target = e.target || e.srcElement;// do something//prevent default actionif(typeof e.preventDefault === 'function'){e.preventDefault();e.stopPropagation();}else{e.returnValue = false;e.cancelBubble = true;}}